FOSSIL BEARS 445 Pleistocene times, was one of the commonest of Carnivorous creatures during the very early times of the present era. It was as huge as a Polar Bear or a Grizzly. The skull is remark- able for the fact that the first three preniolars, which are small in all Bears, dropped out early in life. An immense number of names have been given to what are in all probability the same species as this Cave Bear of remote antiquity. Hyaenarctos is the oldest genus of true Ursidae. It goes back into Middle Miocene times, and ranged over Europe and North Africa. A.rctotJieriu'm is an American genus of Pleistocene times. The likeness of some of the extinct Canidae to Bears has been already commented upon.